Pressure relief score



v,1\.R.Efc il PRESSURE RELIEF scoRE med Jan, s, 196e INvEN'roR ARNOLDRom United States Patent ABSTRACT OF THE DISCLOSURE This disclosure hasto do with an easy opening container wherein a product is packagedtherein and sealed `at a pressure other than atmospheric pressure. Inorder to automatically form a vent opening in the container in advanceo-f the rupture of the container during the opening operation performedthereon, the removable panel portion of the container is provided with aweakening line in the form of a score which underlies the pull tabutilized for opening the container and which is protected by the pulltab. The weakening line is disposed in an area of the container which isinitially stressed prior to the rupture of the' container panel duringthe opening of the container and the strength of the panel along theweakening line is c.

such to assure the initial rupture therealong.

This invention relates in general to new and useful improvements in easyopening container, and more particularly to the formation of a ventopening in a container prior to the tearing out of a removable portionthereof.

Although great strides have been made in the formation of easy openingcontainers of the type wherein a pull tab is provided for facilitatingthe initial rupture of the container and the tearing out of a removablepanel thereof, there still remain problems when the container is packedat a pressure other than atmospheric pressure. If the container isvacuum packed, there is a tendency for implosion. On the other hand, ifthe container is packed at a pressure higher than atmospheric, wheninitial rupture occurs, there is a tendency for the air or other enptrapped gases to rapidly rush out through the initially formed openingcarrying a portion of the contents of the container therewith. Thisinvention particularly relates to the solution of these problems,

This invention specifically has to do with an easy opening container endunit of the full opening type wherein the problem of implosion andexplosion is eliminated by the provision of a specific weakening at aspecific point on the container end unit. In a preferred embodiment ofthe invention, the weakening line is in the form of a score whichextends generally transversely of the axis of the associated pull taband underlies the pull tab so ,as to be protected thereby.

Another feature of the weakening line formed in accordance with thisinvention is that `the weakening line has reversely curved ends so as torestrict the tearing of the endV unit along the weakening line. p Afurther feature of the invention is that the ends of the weakening lineconverge towards one another and are generally directed to the point ofengagement of the pul tab with a peripheral weakening line which definesthe removable panel portion with the weakening line functioning as ahinge line during the initial opening of the container.

A further feature of the invention is the positioning of v "ice With theabove and other objects in view that will hereinafter appear, the natureof the invention will be more clearly understood by reference to thefollowing detailed description, the appended claims and 'the severalviews illustrated in the accompanying drawing:

IN THE DRAWINGS:

FIGURE 1 is aplan view of a can having an end unit formed in accordancewith this invention.

FIGURE 2 is an enlarged fragmentary vertical sectional view taken alongthe line 2-2 of FIGURE 1 and shows the specific details of the end unit.i

FIGURE 3 is an enlarged fragmentary horizontal sectional view takenalong the line' 3--3 of FIGURE 2 and shows specifically the outline ofthe weakening line and the relationship thereof with respect to a rivetwhich secures the pull tab to the end unit.

FIGURE 4 is an enlarged fragmentary vertical sectional view similar toFIGURE 2 and shows the initial rupture of the end unit along theweakening line as an opening pressure is being applied to the end unitthrough the use of the pull tab.

FIGURE 5 is an enlarged fragmentary vertical sectional view similar toFIGURE 2 showing the end unit after the movement of the pull tab to afinal rupturing position prior to the tearing out of the removable panelportion.

Referring now to the drawing in detail, it will be seen that there isillustrated a container in the form of a can which is generally referredto by the numeral 10. The can 10 includes a body 11 which is of aconventional construction and which has the upper end thereof closed bymeans of an end unit, which end unit is generally referred to by thenumeral 12 and which is the subject of this invention. The end unit 12includes an end panel 13 which has the peripheral portion thereofsecured to the body 11 by means of a conventional double seam 14.

It will be readily apparent from FIGURE 1 that the end unit 12 is of thefull opening type in that the end panel 13 is` provided with aperipheral weakening or score line 15 which is disposed closely adjacentthe outer extremity of the end panel 13. In accordance with thisinvention, the end panel 13 is initially ruptured along a portion of thescore line 15 and thereafter the portion of the end panel defined by thescore line 15 is torn out along the'score line. This removable panelportion. is defined by the numeral 16.

-In order to facilitate the rupture of the end panel 13 along the scoreline 15, the removable panel portion 16 is provided with a pull tab 17of the lever type. The pull tab 17 has a central portion thereofpermanently secured to the removable panel portion 16 by means of arivet 18 which is integrally formed with the removable panel portion 16in a conventional manner. The pull tab 17 has a nose 20 which is alignedwith a part ofthe score line 15 and when the opposite end of the pulltab 17 is elevated relative to the removable panel portion 16, the nose20 exerts a downwardly directed pressure on the removable panel portion16 at the score line 15 with the pressure, upon the continued lifting ofthe pull tab 17, being sufficient to effect the rupture of the end panel13 along the score line 15. After an initial rupture of the end panel 13along the score line 15, the pull tab 17 may be utilized in the tearingout of the removable panel portion 16 so as to completely open the can10.

At this time it is' pointed out that the removable panel portion 16 mayhave advantageous configurations. For example, the central portion ofthe removable panelpor tion 16 may be in the form of a recessed panel 21so as' to stiften the end unit. In a like manner, the removable panelportion 16 may be provided with a second score line 22 which is disposedadjacent the score line 15 and in concentric relation thereto. However,the score line 22 is of a lesser depth than the score line 15, as isclearly shown in FIGURE 2, and functions to absorb shock in theremovable panel portion 16 which otherwise might result in theaccidental rupture of the end panel 13 along the score line 15.

It will be readily apparent from FIGURES 2 and 4 that when the radiallyinner end of the pull tab 17 is lifted and the nose 20 is brought intoengagement with the removable panel portion 16, there is a tendency tolift the rivet 18 inasmuch as the rivet 18 functions as the fulcrum. Anylifting force applied to the rivet 18 is, in turn, transmitted to thesurrounding area of the removable panel portion 16. In accordance withthis invention, it is proposed to utilize this highly stressed area ofthe removable panel portion 16 to form a vent opening in the end unitprior to the initial rupture of the end panel 13 along the score line15.

Referring now to FIGURE 3, it will be seen that there is formed in theremovable panel portion 16 immediately adjacent the rivet 18 a weakeningor score line 23. rThe score line 23 has a central portion 24 which isarcuate in outline and which is disposed substantially concentric to theadjacent portion of the rivet 18. At this time it is pointed out thatalthough the rivet 18 is illustrated as being circular in section, itmay be of other section and the contour of the central portion of thescore line 23 will be modified accordingly. The score line 23 also hasreversely turned end portions 25 so that the score line 23 has anoverall outline generally resembling a handle bar mustache.

The specific outline of the score line 23 has numerous advantages. Inthe iirst place, the specific coniiguration and position on the centralportion 24 is such so as to facilitate an initial rupture of the endpanel 13 therealong. It is to be understood that the strength of the endpanel 13 along the central portion of the score line 23 in comparison tothe stress applied thereto during the normal opening of the can is lessthan the strength of the end panel along the score line in comparison tothe stress initially applied thereto by the nose of the pull tab 17.Thus, rupture will positively occur along the score line 23 in advanceof further rupture along the score line 15. As a result, as is clearlyillustrated in FIGURE 4, initial rupture of the end 4panel 13 is in theform of a vent opening 26 which occurs along the score line 23.

It is iirst to be noted that the pull tab 17 overlies the score line 23and thereby prevents accidental rupture of the end panel 13 along thescore line 23. Secondly, when the can is packed at a pressure greaterthan atmospheric pressure, it will be seen that the pull tab 17 preventsa direct blowing out of gases from within the can 10 while notpreventing the desired venting of the can. Further, it will be readilyapparent that since the vent opening 26 is in the form of a crack,minute particles, such as ground coffee, etc. will not escape throughthe vent opening 26 with the outwardly owing gases.

At this time it is pointed out that when the can 10 is packed at apressure less than atmospheric pressure, the vent opening 26 willfunction to permit influx of air so as to equalize the pressure withinthe can 10 with the atmosphere prior to the rupture of the end panel 13along the score line 15. In this manner the vent opening 26 functions toprevent implosion.

A further feature of the specific score line configuration is that byreversely turning the end portions 25 thereof, uncontrolled tearing orrupture of the end panel 13 is prevented. Furthermore, it is to be notedthat the score line 23 facilitates the hinging of a part of theremovable panel portion 16 during the initial opening of the can 10, asis shown in FIGURE 5. This hinging action is facilitated by the terminalends of the end portions 25 being disposed in converging relation andgenerally directed to the point of engagement of the end panel 13 alongthe score line 15 by the nose of the pull tab 17.

At this time it is pointed out that although the pull tab 17 isillustrated as having a hinged connection with the rivet 18, it is to beunderstood that under certain circumstances, the pull tab 17 may be of arigid construction with the necessary hinging action between the pulltab and the end panel being provided by the score line 23 upon therupture of the end panel therealong.

Although only a preferred embodiment of the invention. has beenspecifically illustrated and described herein, it is to be understoodthat minor variations may be made in the construction of the end unit,without departing from'the spirit and scope of the invention, as definedby the appended claims.

I claim:

.1. A container panel of the type having a removable panel portiondefined by a weakening line, a lever type pull tab overlying saidremovable panel portion, means permanently securing said pull tab tosaid removable panel portion with an end portion of said pull tab beingpositioned relative to said weakening line for applying a rupturingeffecting force thereon when the opposite end of said pull tab is movedaway from said container panel, said removable panel portion having anarea thereof which is stressed during the initial movement of said pulltab while applying a force to said container panel along said weakeningline, and a second weakening line disposed in said stressed areaintermediate said first mentioned weakening line and the connectionbetween said pull tab and said removable panel portion and havingreversely turned end portions disposed in converging relation andextending generally towards `said first mentioned weakening line, therelative strength of said removable panel portion along said secondweakening line in comparison to the stress applied thereto being lessthan the strength of said container panel along the lrst mentionedweakening line in comparison to the stress applied thereto whereby saidcontainer panel will first rupture along said second weakening line.

2. The container panel of claim 1 wherein said second weakening lineextends primarily transversely of said pull tab and underlies and isprotected by said pull tab.

3. A container panel of the type having a removable panel portiondefined by a weakening line, a lever type pull tab overlying saidremovable panel portion, means permanently `securing said pull tab tosaid removable panel portion with an end portion of said pull tab beingpositioned relative to said weakening line for applying a rupturingeffecting force thereon when the opposite end of said pull tab is movedaway from said container panel, said removable panel portion having anarea thereof which is stressed during the initial movement of said pulltab while applying a force to said container panel along said weakeningline, and a second weakening line disposed in said lstressed areaintermediate said first mentioned weakening line and the connectionbetween said pull tab and said removable panel portion, the relativestrength of said removable panel portion along said second weakeningline in comparison to the stress applied thereto being less than thestrength of said container panel along the first mentioned weakeningline in comparison to the stress applied thereto whereby said containerpanel will first rupture along said second weakening line, theconnection between said removable panel portion and said pull tabincluding a rivet of arcuate section, and at least a central portion ofsaid second weakening line being in closely spaced concentric relationto an adjacent portion of said rivet.

4. The container of claim 3 wherein said second weakening lineterminates in reversely turned end portions.

5. The container of claim 3 wherein said second weakening lineterminates in end portions disposed in converging relation and extendinggenerally towards that 3,485,410 5 6 portion of the rst mentionedweakening line aligned with tab is provided with an internal hingegenerally aligned said pull tab. with said weakening line.

6. The container panel of claim 1 wherein said pull tab and saidreversely turned end portions extend gener- References Clted allytowards that portion of the rst mentioned weaken- 5 UNITED STATESPATENTS i113 line aligned With Said pull tab- 3356270 1/1968 Khoury 22054 7. The container panel of claim 1 wherein said pull 3,381,848 5/1968Brown 220 54 tab is provided with an internal hinge generally aligned3,404,801 10/1968 Silvr 22g-54 with said weakening line.

8. The container panel of claim 3 wherein said pull 10 GEORGE T. HALL,Primary Examiner

